There are very few investigations on the measurements of total hemispherical emittance of non-metallic materials, in contrast to those on metallic materials. In this investigation, a method for simultaneous measurement of total hemispherical emittance, specific heat and themal diffisivity of non-metallic materials by means of a transient method has been developed.On measurements of thermophysical properties of non-metallic materials, there arises a problem of the thermal garadient produced in a specimen used. An improved transient calorimetric technique to reduced the thermal gradient is proposed in this study.Glass sheets semi-transparent for radiation are selected as a measured by the proposed technique and their results are presented with the thickness as parameter. The corner effect of the specimens due to the local hemispherical emittance distribution on the measured total hemispherical emittance is estimated. It is shown that the proposed technique is very useful for measuring total hemispherical emittance, specific heat and themal diffisivity of non-metallic materials.